CAPE CANAVERAL -Discovery's heat-shield tiles sustained significantly less damage during NASA'ssecondpost-Columbia test flight, a sign that the agency is starting to get adeadly foam-shedding problem under control, a NASA official said.
During post-landinginspections, engineers noted a drop of about 33 percent in the number of damagespots on heat shield tiles on the belly of the orbiter.
There also was almost a 50percent decrease in the number of hits greater than one inch - defects moresusceptible to sustaining further damage when exposed to extreme temperaturesduring atmospheric reentry.
"The vehicle lookedvery good," Thomas Ford, a member of NASA's ice-debris inspection team atKennedy Space Center, said Wednesday. "It's definitely gratifying."
Columbia and sevenastronauts were lost on re-entry in February 2003 when hot gasessurged into the orbiter through a hole created when its heat shield was struckby a 1.67-pound piece of external tank foam insulation about 82 seconds intoflight.
Since then, NASA engineershave modified the tank to try to prevent chunks of foam large enough to causesevere damage from breaking free at critical times during launch.
Ford said 96 hits weretallied on the underside of Discovery after its July17 landing. In comparison, 152 strikeswere found on the shuttle's belly after NASA's first post-Columbia flight lastsummer.
Only 11 strikes larger thanone inch were found on Discovery during inspections conducted on Kennedy SpaceCenter's three-mile runway earlier this month. Inspectors found 21 after lastsummer's flight.
The drop is a sign that safetymodifications meant to prevent the shedding of large foam chunks areworking, Ford said. NASA engineers still are working on other designchanges that should reduce the problem even further.
"Do we have a handleon it? Yes. Is it still a problem? Yes," the Merritt Island resident said."But we're getting better at it."
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